Hazelcast：如何刷新Hazelcast实例？

Question

I am creating a service (ReST) which would be up and running all the time. So in this service I am calling the init method from my spring context which hits the database and loads the required data into the hazelcast instance.

Now I have to ensure that I refresh the hazelcast instance by calling the init method. Let's say that the refresh period is every 6 hours.

Is there a good clean way to achieve this ?

Answer 1

You can use Hazelcast eviction policy for this problem.

<time-to-live-seconds>3600</time-to-live-seconds>

which clears map content every 1 hour and when any request comes it reloads that map content from a loader.

Below is one of the Hazelcast map config

...
    <!--
        Maximum number of seconds for each entry to stay in the map. Entries that are
        older than <time-to-live-seconds> and not updated for <time-to-live-seconds>
        will get automatically evicted from the map.
        Any integer between 0 and Integer.MAX_VALUE. 0 means infinite. Default is 0.
    -->
    <time-to-live-seconds>0</time-to-live-seconds>
...

Or You can add the time while adding data to cache map, after specified time, specific cache map can also be clean.

Answer 2

This can be easily achieved by implementing EntryListener interface provided by Hazelcast.
Implement the below methods and call your init() method.

IMap<> map = hzInstance.getMap("mapName");
map.addEntryListener(new MyMapEventListener());

public class MyMapEventListener implements EntryListener{
    @Override
    public void mapCleared(MapEvent mapEvent) {
        //Make your init call inside this
    }

    @Override
    public void mapEvicted(MapEvent mapEvent) {
        //Make your init call inside this
    }
}

Let me know if this makes sense.